DS+: a method for the identification of cluster substructures

Abstract

The study of cluster substructures is important for the determination of the cluster dynamical status, assembly history, and the evolution of cluster galaxies, and it allows to set of constraints on the nature of dark matter and cosmological parameters. We present and test DS+, a new method for the identification and characterization of group-sized substructures in clusters. Our new method is based on the projected positions and line-of-sight velocities of cluster galaxies, and it is an improvement and extension of the traditional method of Dressler & Shectman (1988). We test it on cluster-size cosmological halos extracted from the IllustrisTNG simulations, with virial masses $14\lesssim \log ({\mathrm{M}}_{200}/{\mathrm{M}}_{\odot })\lesssim 14.6$, that contain on average $\sim 190$ galaxies. We also present an application of our method on a real data set, the Bullet cluster. DS+ is able to identify $\sim 80\%$ of real group galaxies as members of substructures, and at least 60\% of the galaxies assigned to substructures belong to real groups. The physical properties of the real groups are significantly correlated with those of the corresponding detected substructures, albeit with significant scatter, and overestimated on average. Application of the DS+ method to the Bullet cluster confirms the presence and main properties of the high-speed collision and identifies other substructures along the main cluster axis. DS+ proves to be a reliable method for the identification of substructures in clusters. The method is made freely available to the community as a Python code.

13 pages, 8 figures, accepted for publication in A&A

References in corpus (39)

• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Properties of galaxies reproduced by a hydrodynamic simulation
• Concentration, Spin and Shape of Dark Matter Haloes as a Function of the Cosmological Model: WMAP1, WMAP3 and WMAP5 results
• Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56
• Images, structural properties and metal abundances of galaxy clusters observed with Chandra ACIS-I at 0.1<z<1.3
• The relation between velocity dispersion and mass in simulated clusters of galaxies: dependence on the tracer and the baryonic physics
• The speed of the `bullet' in the merging galaxy cluster 1E0657-56
• On the efficiency and reliability of cluster mass estimates based on member galaxies
• Simulating the Bullet Cluster
• The universal distribution of halo interlopers in projected phase space. Bias in galaxy cluster concentration and velocity anisotropy?
• A massive blow for $\Lambda$CDM $-$ the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology
• Substructures in WINGS clusters
• The Three Hundred Project: Dynamical state of galaxy clusters and morphology from multi-wavelength synthetic maps
• The concentration-mass relation of clusters of galaxies from the OmegaWINGS survey
• The Cluster-Merger Shock in 1E 0657-56: Faster than the Speeding Bullet?
• X-ray Substructure Studies of Four Galaxy Clusters using XMM-Newton Data
• Morphology parameters: substructure identification in X-ray galaxy clusters
• The Impact of ICM Substructure on Ram Pressure Stripping
• Substructure and Scatter in the Mass-Temperature Relations of Simulated Clusters
• The Northern Sky Optical Cluster Survey III: A Cluster Catalog Covering Pi Steradians
• A joint SZ-Xray-optical analysis of the dynamical state of 288 massive galaxy clusters
• Robust quantitative measures of cluster X-ray morphology, and comparisons between cluster characteristics
• Dynamical state of galaxy clusters evaluated from X-ray images
• The eROSITA Final Equatorial-Depth Survey (eFEDS): Characterization of Morphological Properties of Galaxy Groups and Clusters
• Accretion of Galaxy Groups into Galaxy Clusters
• X-ray Galaxy Clusters in NoSOCS: Substructure and the Correlation of Optical and X-ray Properties
• The Corona Borealis supercluster: connectivity, collapse, and evolution
• The Three Hundred: Cluster Dynamical States and Relaxation Time Scale
• The Three Hundred project: Galaxy groups do not survive cluster infall
• Investigating the Projected Phase Space of Gaussian and Non-Gaussian Clusters
• Leavers and remainers: Galaxies split by group-exit
• MeerKAT's View of the Bullet Cluster 1E 0657-55.8
• The Distribution of Dark and Luminous Matter in the Unique Galaxy Cluster Merger Abell 2146
• $Suzaku$ and $XMM-Newton$ observations of a newly-discovered early-stage cluster merger 1E2216.0-0401 and 1E2215.7-0404
• Studying galaxy cluster morphological metrics with Mock-X
• Locations and Morphologies of Jellyfish Galaxies in A2744 and A370
• An approximate theory for substructure propagation in clusters
• Morphology of relaxed and merging galaxy clusters. Analytical models for monolithic Minkowski functionals
• Two merging galaxy clusters with very hot shock fronts observed shortly before pericentric passage

Cited by in corpus (12)

• The effect of cluster dynamical state on ram-pressure stripping
• Distribution of merging and post-merging galaxies in nearby galaxy clusters
• Deep view of the intracluster light in the Coma cluster of galaxies
• Euclid: Early Release Observations -- The Intracluster Light of Abell 2390
• Mapping dark matter in the Bullet Cluster using JWST imaging and spectroscopy
• CHEX-MATE: exploring the kinematical properties of Planck galaxy clusters
• New observational recipes for measuring dynamical state of galaxy clusters
• CLASH-VLT: The variance in the velocity anisotropy profiles of galaxy clusters
• Boosting the evolutionary picture of Cl 0024+17 and MS 0451-03: A case study at intermediate-redshift
• Unveiling the shape: a multi-wavelength analysis of the galaxy clusters Abell 76 and Abell 1307
• CLASH-VLT: The Fifth Force in Chameleon Gravity from Joint Lensing and Kinematics Cluster Mass Profiles
• The Limits of Photometric Dynamics: Benchmarking Cluster Relaxation Diagnostics